Add support for saml-specific user model defined by SAML2_USER_MODEL
Add support for saml-specific user model defined by SAML2_USER_MODEL

MiguelSR/djangosaml2,knaperek/djangosaml2,BetterWorks/djangosaml2,writepython/djangosaml2,WebSpider/djangosaml2,writepython/djangosaml2,MiguelSR/djangosaml2,BetterWorks/djangosaml2,WebSpider/djangosaml2,knaperek/djangosaml2